REVIEW ARTICLES

OBJECTIVE: To describe the primary types of antiepileptic drug (AED) interactions by using a mechanistic approach. DATA SOURCES: A literature search was performed using MEDLINE and bibliographies of recent review articles and published abstracts. DISCUSSION: AEDs are associated with a wide range of drug interactions, including hepatic enzyme induction and inhibition and protein-binding displacement. Hepatic induction by AEDs affects the metabolism of a limited number of drugs with low therapeutic indices. Anticipation of induction interactions and careful clinical monitoring may alleviate potential problems. Most commonly used AEDs are eliminated through hepatic metabolism catalyzed by the cytochrome P450 (CYP) and uridine diphosphate glucuronosyltransferase (UGT) enzymes. Phenytoin, phenobarbital, and carbamazepine induce CYP and UGT enzymes. Lamotrigine is a weak inducer of UGT. Valproate is a broad-spectrum inhibitor o